Dynamoelectric machine



Patented Nov. 10, 1942 DYNAMOELECTRIC MACHINE Alvin M. Klingner andMartin Neuner, Fairview, N. J assignors to Bendix Aviation Corporation,South Bend, Ind., a corporation of Delaware Application April 28, 1941,Serial No. 390,816

1 Claim.

This invention relates to dynamo-electric machines, and particularly tocommutator-engaging brush assemblies for use in dynamo-electricmachines.

An object of the invention is to improve the construction of brushassemblies, particularly with respect to the pressure exerted on theindividual brushes to maintain the brush in good contact with thecommutator surface.

It is common practice to employ a strip of spring steel to urge eachbrush into operative position, and to yieldably maintain engagement,regardless of wear which gradually shortens the brush length; and inorder to regulate the de-- gree of pressure of these springs it iscustomary to provide adjusting means. The present invention involvescertain improvements in the manner of making such adjustments and in theadjusting means itself.

Objects of the invention, therefore, include improvements in the methodand means of brush pressure adjustment, in dynamo-electric machines.

These and other objects of the invention will become apparent frominspection of the following specification when read with reference tothe accompanying drawing, wherein is illustrated the preferredembodiment of the invention. It is to be expressly understood, however,that the drawing is for the purpose of illustration only, and is notdesigned as a definition of the limits of the invention, reference beinghad to the appended claim for this purpose.

In the drawing,

Fig. 1 is a transverse sectional view of a machine equipped with brushassemblies embodying the present invention; and

Fig. 2 is a view at a right angle to the viewpoint of Fig. 1.

In these figures there is indicated at I the casing of an electric unit(motor or generator).

The commutator 2 is shown provided with a pair of brushes 3, eachslidably mounted in a bracket 4 projecting from an annular boss 5 on theend wall of the casing I; the brackets 4 being held to casing surface 5by suitable fastening means 6. A flat strip I of resilient, currentconducting spring metal is coiled spirally about (and fastened to) a pin9 adjacent each brush-holder 4, the latter having apertured extensionsII to receive and secure these spring anchoring pins 9. Each spring coilterminates in an outwardly bent, brush-engaging portion 8, whereforethere is applied to each brush a yielding pressure sufficient to insuregood contact with the commutator.

The novel means for regulating, and holding, the desired setting of eachbrush spring I will now be described. Secured to each pin 9 is a toothedsector I 3 with fine pitch teeth adapted to mesh with correspondinglypitched teeth, or threads, of a worm-screw element l4; each screw l4being supported in a bracket I6 forming part of the casing assembly, andeach screw also being provided with a polygonal portion I! accessiblefor application of a wrench thereto, the wrench being insertible throughslots l8 that are normally covered by plates l9. Leads 2| form the usualelectrical connections for the brushes.

Turning of either screw I4, by wrench action or otherwise, will ofcourse vary the tension in the associated spring I, and willcorrespondingly vary the pressure on the adjacent brush 3. The settingthus obtained will remain constant until again revised manually, as theworm l4 acts as a look upon the sector [3 and thereby prevents anyshifting of the inner end of the spring, attached to pin 9.

It will also be seen that adjustments may be made without removing anyof the parts of either brush assembly.

In the claim the term commutator embraces any rotary contact member, orgroup of contact members, whether for direct or alternating cur- What isclaimed is:

In combination with a spirally wound spring having its outer end bearingupon a commutatorengaging brush, a toothed sector connected to the innerend of said spirally wound spring, a wormscrew normally maintaining saidtoothed sector in predetermined position, said worm screw beingrotatable to swing said sector and thereby vary the pressure applied bysaid spring to said brush, a supporting bracket for said worm-screw, anda casing assembly enclosing said wormscrew, said bracket being anintegral part of said casing assembly.

ALVIN M. KLINGNER. MARTIN NEUNER.

